Effect of low-protein diet with supplementing different levels of DL-methionine on production performance of minks in growing-furring period

Abstract

A study was conducted to evaluate production performance of minks in growing-furring period with supplementing DL-Methionine (Met) in low protein diet. Seventy healthy male minks were randomly divided into five groups of 14 minks each. The minks were fed in five kinds of experiment diets (HP, LP, LP+M1, LP+M2 and LP+M3). The dietary protein levels, expressed as percentage of dry matter (DM), were 32% (high protein, HP) and 24% (low protein, LP). LP was supplemented with Met 0.4% (M1), 0.8% (M2) and 1.2% (M3) DM. From mid of September to December 10, apparent digestibility of CP (crude protein), N intake and urinary N excretion were decreased with declining dietary protein levels (p < 0.05) and N retained was the highest in treatment LP+M2. No significant difference was found in total serum protein (TP) and serum urea nitrogen (SUN) among all treatment groups (p > 0.05). Skin length of treatment HP and LP+M2 was higher than that of other groups (p < 0.05). Body length, skin weight, length of guard hair and under hair were not affected by different dietary protein levels (p>0.05). The best performance could be observed in treatment LP+M2. In diet, 24% (DM) protein level with 1.54% Met supplementing was enough for minks during growing-furring period. Dietary protein lowered from 32% to 24% with supplementing Met in diets would result in a 37.9% decrease in urinary N excretion. Furthermore, addition of Met in diets for minks would be beneficial in terms of reducing feed expenses and lessening nitrogen emissions to the environment.

Keywords

minks / low-protein diet / DL-methionine / fur characteristics